Battery life estimation method and battery life estimation apparatus

Abstract

According to an embodiment, a battery life estimation method includes: calculating, for a secondary battery, battery characteristic data at a present time including at least an internal resistance value; storing use condition data including a temperature time distribution and a current value time distribution during an estimation period and a degradation characteristic map representing a distribution of degradation constants with respect to battery voltages and temperatures; and estimating a degradation amount by integrating residence times on a battery voltage temperature plane in the degradation characteristic map based on the battery characteristic data at the present time and the use condition data.

What is claimed is: 
     
         1 . A battery life estimation method comprising:
 calculating, for a secondary battery, battery characteristic data at a present time including at least an internal resistance value;   storing use condition data including a temperature-time distribution and a current value-time distribution during an estimation period and a degradation characteristic map representing a distribution of degradation constants with respect to battery voltages and temperatures; and   estimating a degradation amount by integrating residence times on a battery voltage-temperature plane in the degradation characteristic map based on the battery characteristic data at the present time and the use condition data.   
     
     
         2 . The battery life estimation method of  claim 1 , wherein recursive calculation is performed for an increase in the internal resistance value. 
     
     
         3 . The battery life estimation method of  claim 1 , wherein the period to estimate the battery characteristic is divided into a plurality of sections, and the degradation amount is estimated while updating the battery characteristic in each section for the use condition data in each section. 
     
     
         4 . The battery life estimation method of  claim 1 , wherein the degradation characteristic map is obtained by estimating a behavior of the degradation constant with respect to the battery voltage and the temperature from a degradation constant of a potential and a temperature of an active material in the battery. 
     
     
         5 . The battery life estimation method of  claim 1 , wherein in the degradation characteristic map, a battery voltage-temperature region where the degradation constant is not less than a predetermined value is defined, and a period in which an integrated time of placement of the battery in the region exceeds a predetermined period is calculated as a remaining life from the use condition data by calculation. 
     
     
         6 . The battery life estimation method of  claim 1 , wherein in the degradation characteristic map, a battery voltage-temperature region where the degradation constant is not less than a predetermined value is defined, and a period in which a ratio of a time of placement of the battery in the region exceeds a predetermined value is calculated as a remaining life from the use condition data by calculation. 
     
     
         7 . The battery life estimation method of  claim 1 , wherein a remaining life is calculated as a period until reaching a lower limit of each battery performance. 
     
     
         8 . The battery life estimation method of  claim 1 , wherein a use condition to make the battery usable for a predetermined period is calculated for the battery characteristic at the present time. 
     
     
         9 . A battery life estimation apparatus comprising:
 an estimation unit configured to calculate, for a secondary battery, battery characteristic data at a present time including at least an internal resistance value;   a storage unit configured to store use condition data including a temperature-time distribution and a current value-time distribution during an estimation period and a degradation characteristic map representing a distribution of degradation constants with respect to battery voltages and temperatures; and   a calculation unit configured to estimate a degradation amount by integrating residence times on a battery voltage-temperature plane in the degradation characteristic map based on the battery characteristic data at the present time and the use condition data.